The present invention relates to a liquid-permeable topsheet for a body exudates absorbent article such as a sanitary napkin or a disposable diaper, an apparatus and a method for manufacturing the topsheet.
Japanese Laid-Open Patent Application No. Sho57-82505 discloses a disposable diaper having a topsheet composed of a hydrophobic net-like sheet of thermoplastic synthetic resin and a hydrophilic sheet such as a nonwoven fibrous sheet. The hydrophobic net-like sheet is placed on the hydrophilic sheet and these sheets are integrally bonded together by subjecting them to a heat-embossing treatment.
Japanese Laid-Open Patent Application No. Hei7-328061 discloses a body exudates absorbent article such as a sanitary napkin having a topsheet composed of a liquid-permeable nonwoven fibrous sheet and a plurality of parallel lines of film strips of thermoplastic synthetic resin. The film strips are placed on an upper surface of the liquid-permeable nonwoven fibrous sheet and these are integrally heat-sealed under pressure so that regions of the nonwoven fibrous sheet exposed between each pair of adjacent film strips may retain liquid-permeability.
In these known topsheets, the net-like sheet and the film strips certainly serve to improve a strength of the topsheet, to control a direction in which body exudates flow within the topsheet and to conceal menstrual discharge absorbed in an absorbent core of an article such as a diaper or a sanitary napkin.
However, in these known topsheets obtained by welding the net-like sheet or the film strips onto the nonwoven fibrous sheet, welded areas tend to have a higher rigidity than that at non-welded areas and thereby tend to deteriorate softness of the topsheet as a whole. In consequence, these topsheets are necessarily poor fitting, uncomfortable to wear and cause leakage of body exudates from the article.